Tropical Storm Beryl has brought heavy rainfall and strong winds to the US state of Texas, cutting off electricity to nearly 2 million homes and businesses, and cancelling hundreds of flights.

The storm made landfall as a Category 1 hurricane on Monday morning in the town of Matagorda with winds of 80 miles per hour (130 kilometres per hour), the United States National Hurricane Center (NHC) said.

Hours later, it was downgraded to a tropical storm, but the NHC warned that damaging winds and flash flooding would continue as Beryl pushes inland.

“Life-threatening storm surge and heavy rainfall is ongoing across portions of Texas. Damaging winds ongoing along the coast, with strong winds moving inland,” it said.

Before reaching Texas, Beryl had swept through Jamaica, Grenada, and Saint Vincent and the Grenadines, at times reaching Category 5 wind strengths, the highest level.

It toppled buildings and power lines and killed at least 11 people.

The storm weakened after cutting through the Caribbean but resurged into a Category 1 hurricane as it crossed the warm waters of the Gulf of Mexico.

Before daybreak on Monday, strong wind gusts and torrential rain lashed Texas cities and towns such as Galveston, Sargent, Lake Jackson and Freeport, television footage showed.

By late morning, many fallen trees blocked roads in the city of Houston as the worst of the storm passed with persisting winds and some road flooding.

Ed Gonzalez, the sheriff of Harris County, which encompasses Houston, said on Monday morning that a 53-year-old man died after a tree fell on his home.

The man “was reportedly sitting in house with family, riding out the storm”, Gonzalez said in a social media post. “An oak tree fell on roof and hit rafters”, and the structure then fell on him, the sheriff said.

More than 2 million homes and businesses across Texas lost power as a result of the storm, according to local utilities and data.

Internet connectivity monitor NetBlocks on Monday also reported “significant declines” in connectivity in parts of the state, including the Houston area, after Beryl made landfall.

Meanwhile, several counties in southeastern Texas were under a flash flood warning as thunderstorms unleashed up to 15cm (6 inches) of rain with more expected.

Beryl is the first hurricane since the NHC began keeping records to reach the Category 4 level in June and the earliest to hit Category 5 in July.

It is rare for such a powerful storm to form this early in the Atlantic hurricane season, which runs from early June to late November.

Scientists said climate change likely plays a role in the rapid intensification of storms such as Beryl because there is more energy in a warmer ocean for them to feed on.